I might just be missing it, but now that we have different types of flexibility for weapon mounts, we don't have much in the way of rules for using them. Since SR in general doesn't take facing into account other than GM ruling and common sense, there doesn't seem to be a strong penalty for having a fixed weapon mount. In general, there seems to be little game mechanical difference between a Fixed Flexibility turret and a Flexible Flexibility turret - so long as the gun is pointing in the general direction (say a rear mounted weapon during a pursuit), they have the same chances of hitting a target. Or is there a rule somewhere that makes it more difficult to target a weapon on a fixed mount over a flexible one?
Also, not only did RCCs get no love, they appear to have been subtly nerfed. Clearsight, which used to be universally applicable to all drones, is now drone specific, meaning that sharing autosofts is that much less efficient. They got a slight buff as a result of nerfing drones - drones can now no longer run an autosoft with a rating higher than the pilot rating, where they used to be able to do that. So you can consider the RCC's being able to break that restriction a buff, but it really only seems like one whine being business as usual while seeming better because another system got nerfed.
The book makes extensive reference to the best strategy being a stable of different drones used in concert, but it has made doing so significantly more difficult by making all autosofts drone specific (including the new ones introduced) rather than the handy exclusions of Clearsight and EW. And if you try to compensate by running the software on the drone to free up RCC slots, you can't go as high out of char gen (pilot 4 limits autosoft to 4 for a total pool of 8 as opposed to the previous fixed pilot rating of 3 for drones and a rating 6 autosoft for a dice pool of 9), and the cost to go that high is 2k for the autosoft and 3200 for the pilot upgrade (total 5200) versus 3k for a rating 6 autosoft. Sure, you only have to purchase the pilot upgrade once, but since (barring VM) the drones can only run 2 autosofts, that's 7200 to get two skill at dice pool 8 in Rigger 5.0 vs. 6k for two skills at dice pool 9 under the core. Add in VM, and it is 9200 vs. 9k, still keeping in mind that it is a DP of 8 vs. a DP of 9. One of the major complaints of riggers (or drones) prior to the book was that they had abysmal dice pools, and this simply made it worse until you are swimming in nuyen and have the means to obtain 16F or 24F gear.
10k nuyen (and repurchasing all of your autosofts) to get an extra die in your pool isn't terribly expensive, but isn't terribly great, and still is kinda borderline useful. 20k nuyen and again, repurchasing all of your autosofts to get an actually reasonable DP of 12 is rather expensive, but possibly worth it. However, this is top end and a DP of 12 is rather lackluster.
Maybe it works better in play than it appears on the surface - I'm willing to be convinced - but at first blush, it really looks like an overall nerf.